Slowly Slipping Away
by CreativeFlow
Summary: Isabelle is trying to be careful. After all, she has a lot to lose. Simon is trying to convince her that she is his all, but a new enemy as well as an old one threatens everything. Meanwhile, Clary and Jace are struggling to rekindle the romance and fight for their lives at the same time. Rated T just to be safe.
1. Chapter 1

Disclaimer: I do not own any of the content involving characters, previous plots, or settings. This is strictly a fictional version of the events that take place after City of Lost Souls. All credit goes to the original author of the mortal instruments.

*Note* This takes place after City of Lost Souls.

Chapter One – The Tale of a Vampire

The rain pounded against the windows of the institute without mercy, leaving streaks on the windows that Isabelle had just been forced to clean. Apparently, her mother was not happy with her attitude when she tried to convince her mother that she knew Jace's whereabouts. Alec and she were both sentenced to cleaning duties for a month to give the maid a break.

"Alec can clean them this time," she muttered to herself as she left her room. Though she was only granted permission to see Simon between the hours of four and six P.M., her mother usually let that rule bend a little.

Isabelle wore her mother's black cocktail dress which she stole from the large closet in the room. Maryse wasn't staying in that room anyway. She resided in one of the many guest bedrooms where Robert's belongings didn't dwell. The dress was slim fitting and sleek, wrapping its self around her like cellophane. She also borrowed the black pumps her mother used to wear all the time; she hadn't seen her where them since her father left for Idris.

Sneaking out of the house had never been any trouble for Isabelle because she had a hefty amount of runes at her disposal. But she didn't want to mark herself up and look like some biker chick when she was going on a date. It was far too tacky for her taste. And if she was being honest with herself, she didn't think the burning pain of drawing them was really worth it.

"Going somewhere?" The voice slightly inclined like a sly question. Alec was propped up on the ceiling boards where they were low enough to be reached by the staircase. His blue eyes challenged her with an intense gaze. The crooks of his mouth were raised, flashing his brilliant smile. And his dark hair fell over his forehead loosely like strings. Magnus's scarf was wrapped around his throat making his gaze that much more mesmerizing.

"I'm not in the mood to listen to your comments, Alec. Aren't you supposed to be sucking up to Magnus or are you two still not talking?" She saw his grin quickly fade to a more serious glare. Magnus Bane was still a pretty touchy subject with him.

Isabelle brushed passed him casually, making sure to snicker along the way. "That's what I though."

Simon was waiting for her outside, leaning against one of the street lamps and scrolling through his phone. He quickly closed it and stood up straight to greet her. She liked how alert he was when they were together. It was like had always gone out of his way just to listen to what she had to say.

"You look beautiful," he said, planting a kiss on her cheek. His lips were soft and cold, brushing against her cheek. A tingling sensation ran through her body like liquid nitrogen was being poured into her veins.

"You don't look so bad yourself." Compliments weren't really Isabelle's thing. She could tear a person down and make them feel worthless with one whip of her tongue. But being nice?

She noticed he was wearing the leather jacket and combat boots she had picked out for him. But he wasn't wearing one of his usual slogan tee shirts. Instead, a white shirt with nothing on it covered him. His hair was cut. Not completely buzzed off-it wasn't even that short. But it seemed shorter because of the jagged cut of his bangs. She liked the way he looked because she could stare into his eyes as long as he would let her.

"What are we going to be doing?" Simon had left her completely in the dark. He wouldn't tell her where they were going or what they would be doing. Isabelle had to admit, the mystery to him was an attractive quality.

"I thought we'd go for a walk first. Then you'll find out." He grabbed her hand, pulling her closer to him. She could smell his laundry detergent-it smelled like lingering oranges. Being this close to most boys, she'd be able to feel their breath. And it was quite startling to think that he didn't breathe. But Isabelle was used to Simon now. They knew each other, knew what they did, who they were, what they liked. She couldn't remember the last day she had gone without at least talking to him on the phone.

But with Simon came the nauseating thought of Clary. Isabelle wasn't completely convinced that there was nothing between them anymore. She wasn't prepared to give her whole heart to someone who wasn't willing to do the same. It wasn't exactly that Simon wasn't willing; it was more like it wasn't possible for him to forget his feelings for Clary. It might have been too late for Isabelle to stop herself. Every day, her heart inched its way closer and closer to the vampire boy who claimed to care about her.


	2. Chapter 2

Chapter Two – What Just Happened?

Isabelle looked so beautiful to Simon. She always had and always would. There was no doubt in his mind that she was, by far, the most attractive person he had ever seen. And she admitted to caring about him. No girl, aside from Clary and his mother, ever told him they cared about him.

Her hand was warm in his. He could feel the blood pumping through her veins like a rhythmic drum. The tempo was both consistent and irregular. It wasn't hard to tell that Isabelle was on edge-when wasn't she? But this felt different. He noticed it the last few times that had been together. Her heart was beating quicker, shorter. That may have just been because he was so used to listening to her heart beat at a slow and steady pace when he would lie next to her until she fell asleep.

He hadn't been doing much sleep himself. Occasionally, he would go visit his mother and spend the night there. But it was safer for her and him if he just remained at Jordan's house. Not that he was getting much sleep there either. Maia practically moved in. But during the daytime, the apartment was all Simon's, because Jordan and Maia were off doing whatever werewolves do. So Simon spent his time with Isabelle or Clary and occasionally, Jace.

The light New York breeze blew against his face making for a better setting. Isabelle, who was walking with him closely, looked a little cold. He shrugged his jacket off and placed it over her shoulders, knowing that she wouldn't like it-Isabelle didn't like any gesture that made her feel weak and vulnerable. But her health and safety meant more to him than her pride. Even though he was an undead creature who couldn't be affected by the climate, she wasn't.

She didn't say a word. She just kept walking in step with him. He liked that his steps were more graceful now, but he was still a bit clumsy around her because of the effect she had on him. He got nervous around her, his not-so-beating heart raced and butterflies crowded his stomach.

"Are you going to tell me where we're going?" She sounded both curious and irritated, making him smile. Isabelle Lightwood certainly did not like to be left waiting.

"If I tell you, it won't be a surprise now, will it? You just have to learn to be patient," he said very matter-of-factly. He could see a smile grin stretch out her lips. He knew her face now like the back of his hand. He knew where every little scar was and he knew where she had her birthmark-it was on the back of her shoulder blade.

Finally, they reached what Simon was looking for. Just over the stone pathway of the park was a small cliff. He and Clary used to pretend they were falling off of it when they were little. One time, she even fell in. Bellow the cliff, a stream of fresh water ran vigorously. It was a shallow stream, only reaching up to his knees.

"Are we going swimming?" She sounded almost confused. But he just chuckled and sat on the edge of the small cliff after rolling his jeans up past his knee and dangling his legs into the water. Isabelle quickly joined him.

"I like it here," he said quietly. "It's so peaceful. I found when I was little and dubbed it my thinking spot."

"I can see why you like it. It's untouched, unlike everything else in the world." She sounded bitter, hateful even. And he knew she was reminiscing about the day of Max's death. Though Isabelle knew in her heart that there was no possible way she could save him-which Simon often reminded her when she got like this-she still beat herself up over it. And there was only one way to deal with a self-loathing Isabelle. Comfort her.

Simon wrapped his arm around her, pulling her closer to him. He could smell her perfume. She was still wrapped up in his jacket, but he didn't mind. It made her seem younger, like a child. That was probably the only time she'd ever look so innocent.

Quickly, a thought hit him. He remembered what he really came here for. He pushed aside large rock that was planted on the ground next to him revealing a small box.

"What's that?" Isabelle asked curiously. "You aren't going to propose to me, are you? I think we're a little young for that."

"No, I'm not proposing. I'm not entirely sure you'd say yes. But that's beside the point. It's a gift I got for you." His skinny fingers cradled the box as the other hand opened it. It was a bracelet.

"It's beautiful," she said with a gasp. He knew that she liked jewelry. But this wasn't just jewelry, it was thoughtful. The silver chain had small little charms hanging off of it, each with a word engraved on it.

"The words on it are what I think of you."_ Brave, beautiful, smart, strong, independent, caring._ "But there's no bracelet in the world that can hold all of the words I think of you."

She hugged him so tightly, he thought he might die. The warmth radiated from her like the sun. He could smell her blood as if it were inside his nostrils. The hunger pulled at his stomach, making it churn. But he fought it like never before. Sometimes, it was just what he had to do.

Before he could get himself together, something hit him knocking him into the stream and soaking all of his clothes. Isabelle followed soon after, crashing on him. Simon looked up to see the attacker, only to Sebastian standing before them. "Hope I'm not interrupting."


	3. Chapter 3

Chapter Three –

Something strange was happening, Jace could feel it. It was in his gut. The first thing he did was call Clary. He knew that if she were hurt, he just couldn't live with himself. Though he still wasn't allowed to leave the institute without supervision, he was still allowed to make calls.

After three rings, Clary finally picked up much to his relief. "Hello?"

"Are you alright?" he asked quickly.

"Yeah, I'm just waiting for a call. Simon is on a date you know. I got to help him plan it." She sounded almost proud of herself making Jace smile automatically. He enjoyed the way she got pleasure from something as simple as helping a friend. She was just a good-hearted person.

But that was it. At the hearing of the name, Jace's stomach knotted making him so dizzy he had to sit down. "Clary, where are they?"

"Oh, no. I'm not telling you so you can go mess it up on him," she said with aggravation.

"Clary, I think they're in trouble. Please, tell me where they are," he begged her. Her being a stubborn person didn't help at all. She would always doubt him when it came to the daylighter simply because he meant so much to her. Sometimes, it really hurt him. Sometimes, he thought Clary was going to leave him for Simon. But loved her and if that was her choice, he would respect it.

After getting the location off Clary, he hung up and ran straight for the weapons room. Grabbing a seraph blade and place a few sharp-edge stars in his back pocket, he made a run for it.

"Where do you think you're going?" Alec stood just outside the institute with a disappointed look on his face. Jace found it quite annoying how, ever since the breakup, Alec had a little too much time on his hands.

"Get out of my way, Alec. Simon and Isabelle are in trouble," Jace hissed while grabbing his stele. Forging the runes into his skin was painful. It burned his arm like hot rocks. But he knew that they would make him better, faster, stronger. Alec watched as he carved the patterns into his skin with extreme focus.

"I know, Jace. I felt it too." Alec was strange that way. He was the only person who didn't doubt Jace or think he was being irrational. It made Jace realize-more than he already did-that Alec was his real brother no matter what biology said.

"But you can't do this alone. You're still a little weak. Let me come with you," he said almost pleading.

"Fine. I guess I could use the help." Help wasn't something Jace liked to ask for. But he wasn't an idiot and he took it when it was offered. Alec pulled out his own stele, plunging it into his skin and carving in symbols. Strength, agility, stealth, speed and silence.

They ran through the park, their feet soundlessly pounding into the ground. Jace felt his blood pumping through him like hot fire. His lungs rose with air to full capacity before releasing the air again. Timing his breath was everything. It was something Valentine had showed him-he told him it was how marathon runners won, and winning was everything. If he could time his breath just right, it would help keep him going while he sprinted.

A shriek was audible from where they were. Alec's blue eyes met his, the horror blatant. Just encouraged himself to push himself harder, to run faster than ever. There was no telling what limits he had, so why not set them himself? Alec tried to keep up with him. He was only a few feet behind. But Jace wasn't going to slow down for anything. His sister was in trouble. His friend was in trouble.

Jace often tried to not think of Simon as a friend, but he was. Simon could be funny when he wanted and saved Jace's life a few times. Plus, he meant the world to Clary so that had to count for something.

Jace finally got to the stream Clary had told him about. Much to his dismay, he saw Isabelle and Simon…and Sebastian.

"Well, well, well. If it isn't my little brother," he said in his venomous voice. It was like ichor filled his mouth.

"We've been over this quite a few times. I'm not your little brother. I'm not even a cousin, a friend, or an acquaintance for that matter. I'm your enemy." Jace pulled out the seraph blade, whisper its name to it faintly. He hadn't realized that Alec had already done the same.

He peaked around Sebastian's muscular build to see the others. Isabelle was unconscious, bleeding from the head. Simon was sitting in the water clutching her limp body. For a moment, Jace thought she might be dead. But he quickly pushed such a repulsive thought away.

Jace planted his feet firmly on the ground, preparing to lunge. But Sebastian quickly waved the intention down. "Don't even try it," he said methodically. His silver hair whipped around his head as he turned to look at Simon. "Or he'll be next. I noticed his little scribble is gone. Guess now he can see what real fear is like."

"What do you want?" Alec moved closer towards him like a stalking cat. There was no telling what he would do to the guy who murdered his little brother. And if Jace was being honest, he wasn't sure he'd stop him.

"What I've always wanted. I want an army to bow down before me. A new generation of shadowhunters. Better ones. And I'd also like my sister back."

"Like hell. You lay a finger on her and I'll decapitate you," Jace shouted with fury. There was no way he was going to late that demon child near Clary ever again even if he was to be possessed again. He would fight it with everything he had.

"I'd like to see you try. See, I've been getting stronger and stronger and you all just stand around and watch. I haven't heard of much Clave activity. That's a pity. I was quite anticipating getting to slay them all myself. But I have more important things to do right now. Bring me Clary Fray in this very spot. You have one week or I not only kill all of you. But I'll kill your families, your friends, and whatever other person I happen to come by on the trip home." There was something starteling about the way he spoke. It was like listening to a sadistic serial killer. He _was_ listening to a sadistic serial killer.

"Fat chance of that happening," Jace huffed sarcastically. There was no way Jace was just going to hand over Clary to Sebastian. It just wasn't likely.

"We'll see about that. I'm just going to let the thought settle with you. I'm sure Clary won't mind being the death of countless innocent people. But that's your call." Like a wisp of wind, he disappeared vanished into thin air.


End file.
